Grisanti pleaded guilty in October 2010 in a federal wire fraud scheme through his business, Grisanti Rebel Cheverolet.
He also repaid a $2 million loss to Regions Bank as a result of his scheme.
Grisanti was a key government witness in its prosecution of Hal Neilson, a Oxford FBI agent accused of lying about his financial interests in the Oxford FBI Building where he worked.
After a two-week trial in late 2010, a jury found Neilson not guilty on some counts, then prosecutors dropped those the jury could not decide on.
Before Grisanti was sentenced to one day with credit for time served in May 2011, the U.S. Attorney’s Office asked the court for leniency because of his cooperation in the Neilson case.
He also was sentenced to three years of supervised release.
Monday, U.S. District Judge Michael P. Mills signed his early release from probation after it was recommended by the U.S. Probation Service.